package com.hmdp.service.impl;

import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IVoucherService;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.util.Collections;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
@Slf4j
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Resource
    private IVoucherService voucherService;

    @Resource
    private RedisIdWorker redisIdWorker;

    @Resource
    private ISeckillVoucherService seckillVoucherService;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private RedissonClient redissonClient;

    /*@Override
    public Result seckillVoucher(Long voucherId) {
        //1.查询秒杀券
        SeckillVoucher voucher = seckillVoucherService.getById(voucherId);

        //2.查看是否开始
        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
            return Result.fail("秒杀尚未开始");
        }

        //3.判断库存是否充足
        if(voucher.getStock()<1){
            return Result.fail("库存不足");
        }

        Long userId = UserHolder.getUser().getId();
        //创建锁对象
        //SimpleRedisLock lock = new SimpleRedisLock("order:" + userId, stringRedisTemplate);
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //获取锁
        boolean isLock = lock.tryLock();
        if(!isLock){
            return Result.fail("一人只允许下一单");
        }

        try {
            //获取代理对象，解决事物失效问题
            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
            return proxy.createVoucherOrder(voucherId);
        } finally {
            //释放锁
            lock.unlock();
        }
    }*/

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }
    //创建阻塞队列
    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);
    //创建线程
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    @PostConstruct
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    private class VoucherOrderHandler implements Runnable{
        @Override
        public void run() {
            while (true){
                try {
                    //1.获取队列中的订单信息
                    VoucherOrder voucherOrder = orderTasks.take();
                    //2.创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("处理订单异常",e);
                }
            }
        }
    }

    private void handleVoucherOrder(VoucherOrder voucherOrder) {
        Long userId = voucherOrder.getUserId();
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        //获取锁
        boolean isLock = lock.tryLock();
        if(!isLock){
            log.error("不允许重复下单");
            return;
        }

        try {
            //获取代理对象，解决事物失效问题
            proxy.createVoucherOrder(voucherOrder);
        } finally {
            //释放锁
            lock.unlock();
        }
    }

    private IVoucherOrderService proxy;
    @Override
    public Result seckillVoucher(Long voucherId) {
        //获取用户id
        Long userId=UserHolder.getUser().getId();

        //1.执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(), userId.toString()
        );

        //2.判断结果是否为0
        int r = result.intValue();
        if(r!=0){
            //2.1.如果不为0，没有购买资格，报错
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }

        //2.2.如果为0，有购买资格，将下单信息保存到阻塞队列
        VoucherOrder voucherOrder = new VoucherOrder();
        Long orderId = redisIdWorker.nextId("order");
        voucherOrder.setId(orderId);
        voucherOrder.setUserId(userId);
        voucherOrder.setVoucherId(voucherId);
        //2.3放入阻塞队列
        orderTasks.add(voucherOrder);

        //3.获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();

        //3.返回订单id
        return Result.ok(0);
    }

    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        //4.一人一单
        Long userId = voucherOrder.getUserId();

            //4.1查询订单
            Integer count = query().eq("user_id", userId).eq("voucher_id", voucherOrder).count();

            if (count > 0) {
                log.error("用户已经购买过一次");
                return;
            }

            //5.扣除库存
            boolean success = seckillVoucherService.update().setSql("stock=stock-1")
                    .eq("voucher_id", voucherOrder).gt("stock", 0)
                    .update();

            //扣除失败
            if (!success) {
                log.error("库存不足");
                return;
            }

            save(voucherOrder);

    }
}
